Liquid ejectors



Feb. 12, 1963 R. A. EYMAN 7,

LIQUID EJECTORS Filed May 15, 1958 4 Sheets-Sheet 1 INVENTOR Ralph/4.Eymam BYQ.

li/S ATTORN EY 4 Sheets-Sheet 2 R. A. EYMAN L'IQUID EJECTORS E M 0| 1 J:E ill:

l Hlm z M??? 1" Feb. 12, 1963 Filed May 15, 1958 I NVENTOR liaafi A.Eymam CQWW fi/Is ATTORNEY Feb. 12, 1963 R. A. EYMAN 3,077,163

LIQUID EJECTORS Filed May 15, 1958 4 Sheets-Sheet 3 P K 79 3 x? INVENTORRalph A. Eyman,

BYQQQ ms ATTO RN EY Feb. 12, 1963 R. A. EYMAN LIQUID EJECTORS 4Sheets-Sheet 4 Filed May 15, 1958 FL I Ralf/Z A Eyman INVENTOR M /l/;ATTORNEY United StatesPaten't ()fitice 3,077,153 Patented F eb. 12, 19633,077,163' LIQUID EJECTORS Ralph A. Eyman, Miami, Fla, assignor to RalphE. Carter Company, Hackensaclr, N.J., a corporation of New York FiledMay 15, 1958, Ser. No.'735,66 1

. 25 Claims. .(Cl. 103-448) The present invention relates toimprovements in pneumatic pumping systems, and more particularly topumping apparatus operating with a compressed aeriform mediumfor'periodically lifting to a' higher level liquids, or liquids mixedwith solids, which are accumulated in a receptacle. The improved systemis particularly suitable for use in many types of sewage ejectors eventhough the field of its' sistbasically of a receiver having a fixedcapacity to ac-.

cumulate the intermittently flowing liquids, or liquids mixed with solidmatter, and of an apparatus for periodically evaluating the receiver bylifting its contents to a higher level. The receivers, also' calledpots, are'eq'uipped with suitable actuating devices which latter may beresponsive to the combined weight of the receiver and its contents, ormay be so installed as to set the evacuating apparatus into operationwhen the liquid in the receiver reaches a predetermined highest level.Many known ejector systems, as well as the apparatus of this invention,utilize a compressed aeriform medium which, by being released in to thereceiver, expels the liquid contents through suitable discharge pipingto a higher level, whence the sewage may continue its gravity flow tothe treatment plant or into another receiver, if necessary.

I According to a more recent proposal disclosed in Patent No. 2,656,794granted on October 27, 1953, the receiver is in the form of a length ofpipe through which the raw sewage is led, and the controls forevacuating apparatus are'mou'nted directly in the piping. Tn is patentfurther proposes the use of an actuating device for'the evacuatingsystem which is responsive to changes in liquid level, and of a holdingdevice whose purpose. is to maintain the actuating device in operationwithin a predeterrnined pressure range in the collecting piping.However, when a compressed gas is introduced into the system at a relatively slow rate, the liquid level in the collecting piping drops belowthe actuating device and rises a proportional amount in the dischargepiping. Assuming that the gas is, introduced at a rate slow enough tocreate anegligible bacsi pressure, the difference between theliquidlevels in the collecting and discharge piping may be so slightthat the lower limit oi the pressure range within which the holdingdevice operates may never be reached. If, on the other hand, compressedgas is introduced at a rate fast.

enough to create dynamic back pressures higher than the lower limit ofpressure range within which the holding device operates, temporarysurges of short duration will occurin most cases whereupon the pressuredrops below the lower limit of the required pressure range. The resultin both instances is useless cycling and irregular pulsating operationof the patented apparatus.-

According to a further proposal in the aforementioned patent, thecontrol system may consist of an air compressor, a starting deviceactuatable by the liquid at a predetermined level in the collectingpiping, and a timing arrangementwhich latterkeeps the compressor inopera l vice shuts off the supply of compressed gas.

tion for a predetermined period of time considered sumcient to eject allor essentially all of the material collected in the piping. Such systemscould be considered satisfactory in instances when the pumping deviceneed not operate against substantial back pressure. In a pumping stationwith pressurized lines, however, such. pumping devices whose controlsinclude merely a starter and a timer are unsatisfactory because theconditions in pressurized lines are unpredictable and, if a gas isintroduced for a predetermined period of time, it may fully evacuate thereceiver in one instance but will'cause only partial evacuation in otherinstances when the pressure conditions in the lines change.

An important object of the present invention is to provide a controlapparatus for evacuation of receivers in liquid ejectors which insurecomplete evacuation of accumulated liquids irrespective of pressurefluctuations in the receiver.

Another object of the invention is to provide a control apparatus of theabove described character which is responsive to the pressuresprevailing in the receiver only after elapse of a fixed time periodsubsequent to the start of liquid evacuation.

' An additional object of the invention is to provide an apparatus ofthe above described character whose'opera tion is fully automatic andwhich may be installed with equal efiiciency insystems employing a potor a pipe as the liquid collector. V

A further object of the invention is to provide an ap paratus adapted toevacuate a sewage receiver which is of simple construction, which'isfully automatic, and which may be installed in existing ejectors.

A still further object of the invention is to provide in a pumpingapparatus of the above characteristics an inlet trap so located withrespect to the receiver that the uni' flow valve, which normallyprevents entry of additional liquids during the evacuation cycle, sealsagainst liquids rather than against gases.

The improved system consists essentially of a starting device so mountedas to be actuatable by the liquid in a receiver at a predetermineduppermost level in the latter, a source of compressed aeriform medium,piping connecting the source of compressed aeriform medium with thereceiver, and a control mechanism operable by the starting device insuch a way as to introduce a coinpressed gas into the receiver when thelatter filled with liquid to a predetermined level. The control arses:

anism is coupled with a suitable time delay which main tains the supplyof compressed gas into the receiver for a fixed time period regardlessof the pressures prevailing in the receiver, and withpressure-responsive means which latter stops the c'ontrol apparatusafter the time delay; has already completed its operation, i.e. afterthe condi tions in the liquid receiver are sufiiciently settled topermil: consistently uniform reduction in pressure therein to' thelowermost level at which the pressure responsive'de- Thus, the pressureresponsive means becomes effective only after the initial andoftenunbalanced conditions in the receiver, arising from suddenintroduction of a compressed gas, are sufficiently controlled and stableso that the subsequent reduction in pressure, preferably close toatmospheric pressure when the liquid receiver is sufficiently evacuated,is always uniform and the pressure responsive means actually turns offthe apparatus at a time when the receiver is empty. The receiver. isthen connected to atmoshere and the one-way control device in the inletpiping permits renewed inflow of liquid material into the receiver tofill the latter to a predetermined maximum level when the liquidevacuating cycle is repeated in the. same way.

As it is well known that a valve will seal better against a liquid thanagainst an aeriform medium, the invention provides an inlet trap in andadjacent to the tcrmmal of inlet piping leading the liquid into thereceiver, and the customary inlet check valve is then located on theupstream side of the trap, whereby, upon introduction of a compressedgas into the receiver, the liquid in thetrap is forced .against thecheck valve to seal same effectively while the evacuation ofliquid'takes place.

The time delay may be of varied designs. For example, an electriccontrol system employing time delay relays may be used, or a delayoperating with a liquid medium may be employed. The pressure-responsivedevice which shuts oil the supply of compressed gas may be a valve ofknown construction, for example, a diaphragm valve or the like, and isso coupled with the line leading to the source of compressed gas as tointerrupt the flow of gas into the receiver at a predetermined minimumpressure prevailing in the receiver after the time delay has completedits operation.

The starting device which triggers the operation of my novel apparatusmay be- (a) A float of known construction disposed close to the top ofthe receiver so that the liquid lifts the float and thereby opens thepath for compressed gas at a predetcrmincd maximum level in thereceiver; or

(b) An electrode extending into the receiver so that the liquid, uponreaching its uppermost level, closes a path between the electrode and,for example, a grounded wall of the receiver to energize one or morerelays which latter, due to the provision of suitable holding circuits,remain energized even after the electrode is out of contact with thedescending liquid material.

As before stated, the novel system is equally applicable to ejectorsystems employing a sewage collecting pot or those employing a length ofpipe for collecting .theliquid materials. in the following more detaileddescription of my invention and in the claims, the term receiver isintended to embrace either a pot or a length of piping whenever areceptacle for liquids is referred to.

Since the starting and the pressure-responsive apparatus may beinstalled in immediate proximity of each other, the liquid evacuatingapparatus may be designed as a very compact unit and thus requireslittle room for its installation. If electric current is not available,the apparatus may be constructed with a hydraulic time delay and may usea constant source of compressed gas located at some distance from theejector which source may be connected with more than one ejector. Thehydraulic delay preferably consists of a novel assembly speciallydesigned for use in liquid ejector systems of this invention and may beintegrally coupled with the pressure-responsive device in such a way asto prevent the latter from shutting off the supply of compressed gas fora fixed time interval starting from the moment when the gas is firstintroduced into the receiver.

Many additional features, advantages and attributes of my improvedapparatus for evacuating liquids or mixtures of liquids and solids to ahigher level wi'l become apparent in the course of the followingdetailed description of certain embodiments selected for illustration inthe accompanying drawings, and the true scope of my invention will bepointed out in the appended claims.

In the drawings,

FIG. 1 is side elevational View in partial section of one form of theexpanding-gas ejector;

FIG. 2 shows a hydraulic control apparatus for the ejector systemillustrated in FIG. 1;

FIGS. 3 and 4 illustrate two forms of electrically operated controlapparatus; and

FIG. 5 shows a modified expanding-gas ejector in which the pot isreplaced by a length of pipe.

Referring now in greater detail to the illustrated embodiments,'andfirst to FIG. 1, there is shown a liquid ejector pump 1% comprising aninlet pipe 11, a check" valve 12, an inlet trap 13, an ejector pot 14, adischarge trap 16, gas expansion pipe 17, a discharge pipe 18, gassupply conduit 1%, controls actuating element 20, and a gas releasechamber 21. The gravity main 22 forms no part of the pump; it receivesthe liquids or the mixture of liquids and solids lifted by the pump 10from its pot 14 through pipes 17 and 18 by means of compressed gasentering the system through the supply conduit 19 and escaping into thegas release chamber 21. The element 20, representing but one form of theactuating means for the control apparatus, is shown in greater detail inFIG. 2 further illustrating the hydraulic time delay system forintroduction of compressed gas into the supply conduit 19.

At the beginning of an operating cycle, a small quantity of liquidremains in the discharge trap 16 from the previous cycle, filling thedischarge trap 16 to the approximate level indicated by line A-A. Liquidfrom the previous cycle also fills the inlet trap 13 to the approximatelevel of line B B. New liquid, for example, raw sewage, flows by gravityinto and through the inlet pipe 11 and fills the pot 14 and gasexpansion line 17 up to the level indicated by line CC. During thisfilling stage of the cycle, the air which is displaced by the liquid inpot 14 is free to escape into atmosphere through the open line 19. Onthe downstream side of discharge trap 16, i.e. in the lower part of thegas expansion pipe 17, the air displaced by the rising liquid is free toescape through the discharge line' 18 and into the gas release chamber21 which, too, is open to atmosphere.

As the liquid level rises toward line C-C, the liquid lifts element Ztlwhich, when the level C-C is reached, directly or by remote control,closes the gas pipe 19 to atmosphere and introduces compressed gastherethrough. The gas penetrating into the pot 14 exerts suificientpressure against the liquid in inlet trap 13 to close inlet check Valve12 and to force the liquid up the gas expansion line 17 and dischargepipe 18 into the gravity main 22, the gas escaping into the chamber 21.As the inlet check valve 12 is closed, no new liquid can enter whilecompressed gas is introduced into the pump 1% The liquid level descendsto the line DD.

The main advantage of providing an inlet trap is in that the inlet checkvalve seals much better against liquid than against gas. Thus,compressed gas entering through conduit 19 exerts pressure against theliquid in inlet trap 13,

and the entrapped column of liquid in turn closes the inletcheck valve12.

The column of liquid in the gas expansion pipe 17 has a slight momentumand continues to rise in said pipe under the influence of advancingcompressed gas. However, regardless of this momentum, the gas starts tobubble up and through the liquid and entrains the liquid through thedischarge pipe 18. The resulting mixture of gas and liquid in theexpansion pipe 17, being lighter than a solid liquid column, reduces thehead on gas accumulated in the pot 14. This enables the gas to expand asrapidly as the head is lowered, the head in turn being lowered evenmore.

as the gas expands, thus creating a chain reaction until the expandinggas has developed enough velocity to carry most of the remaining liquidin the expansion line 17 up and through the discharge pipe 18. The gascontinues to escape up and through pipes 17 and 18 until the pressure inthe receiver approaches atmospheric pressure when the gas can no longerexpand and the small amount of remaining liquid drops back into thedischarge trap 16. As the pressure in the pct 14 nearly approachesatmospheric pressure, a device connected to line 31 and responsive tosuch drops in pressure in the receiver 14 shuts off the supply ofcompressed gas through pipe 1 and opens the latter to atmosphere tocomplete the ejection cycle of the pump 10. The pressure at which thisdevice beminimum comes responsive will hereinafter be called the holdingpressure. I v

The inlet valve 12 reopens and permits new liquid to enter by gravityfeed through the pipe 11 to again fill the receiver 14 up to the level0-0. The gas expansion and liquid ejection cycles are then repeated asabove described.

Results of extensive tests conducted with actual working models indicatethat the total time necessary for the completion of the final or gasexpansion stage, that is, the interval between that time when the liquidin the receiver reaches level D--D and the time when the pressure dropsto or nearly approaches atmospheric pressure, is surprisingly short,lasting from less than one second for low lifts to two or three secondsfor higher lifts. The reaction is more violent as the lift, i.e. thedifference in levels of pot 14 and gravity main 22., increases. Thequantity of liquid remaining in the pump is about the same.

Although, under certain exceptional circumstances, the resultingpressure momentarily reaches atmospheric pressure, in most cases it onlyrather closely approaches the atmospheric pressure. In every instance,after the remaining liquid drops back into the discharge trap 16, theresulting pressure creates a slight back pressure against the incominggas before the supply conduit 19 can be shut off to further entry ofcompressed gas and be opened to atmosphere. The maximum value of suchrather slight build-up in back pressure will hereinafter be called themaximum critical pressure. In order to insure proper functioning of thepressure-responsive device, the minimum holding pressure must be equalto or higher than the maximum critical-pressure. However, in order toevacuate the maximum amount of, liquid, the minimum holding pressuremust be as close to atmospheric pressure as possible. The-minimumholding pressure then becomes equalto the maximum critical pressure. I

The discharge trap 16 is so designed as to insure that maximum amountsof liquid are pushed up the line 17' to empty pump 10 before theexpansion phase of the compressed gas is started. The pump 10 operatesbest when the gas expansion pipe 17 'is in vertical position though, asshown in FIG. 1, it need not necessarily be vertical. As the inclinationof pipe 17 to the vertical increases, the amount of liquid remain inginthe system atthe endofea'ch liquid evacuating cycle also increases.By.further inclining the pipe,-its angle. to the verticalreaches acritical magnitude when thegas escapes on top of the liquid instead ofmixing withit to. reduce its density. By increasing the angle of pipe17,: its length also increases so that the volume of free gas stored inthe pot 14 in proportion tothe physical total volume of the receiverplus that of the expansion pipe 17 becomes less, thus destroying some ofthe ability of gas to completely expand with sufiicient force andvelocity to become eiiective. v The angle indicates the inclination ofgas expansion pipe 17 to the vertical. While, and as already statedhereinbefore, the performance of the pump is improved if the line 17 isvertical, under certain circumstances, for example, due to thepeculiarities of terrain over which the piping is led. slight or evensubstantial inclination of pipe 17 to vertical may become necessary.

In FIGS. '2 to 4, there are shown three types of control apparatus forintroduction, or cutting off the supply, of compressed gas into the pump19, as well as for establishing or interrupting the communicationbetween atmos-' phere and the pct 14 for escape of air on the upstreamside of the discharge trap.

\ The requirements which this control apparatus must satisfy for properoperation of the above-describedpump system will be best understood byshortly reviewing the op{ eration of the pump. As shown in FIG. 1, theliquid level rises while the infiowing liquid progressively fills thepct 14 until theliquid reaches its maximumlevel indicated by line C-C.The control apparatus not only must be able to actuate one or moredevices to shut oii the gas line 19 to atmosphere and to. introducecompressed gas into the system, but also to maintainsuch device ordevices in operative position until the receiver is fully evacuatedregardless of the pressure conditions prevailing therein since the dropin gas pressure to minimum holding pressure should occur only when theejection cycle of the pump is completed; otherwise, too much liquidwould remain which would considerably reduce the efiiciency of thesystem.

The control apparatus is actuated by the liquid at a certain level andis held in operative position by the back pressure exerted by liquidagainst the incoming compressed gas. This back pressure will hereinafterbe called holding pressure. The control system is released, i.e.returned to inoperative position, when the holding pressure is soreduced that it reaches its minimum value. However, the control systemcan be released only after having been held in operative position by asuitable time delay for a fixed period of time regardless of pressureconditions prevailing in the receiver. This is necessary because, in thevery instant when a compressed gas is intro duced slowly into thereceiver 14, the liquid level immediately drops below line C--C and thuspermits descent of the sensing device 20 while the liquid level risesonly slightly in the gas expansion pipe 17. The resulting static backpressure acting through conduit 31 is so close to atmospheric pressureto be below the minimum holding pressure, and thusdoes not afiect thepressure-responsive device sufficiently to maintain the latter in aposition in which it introduces compressed gas intothe pump system. Thetimedelay is also necessarywhen'the compressed gas is introduced at ahigher rate sufiicient to cause asurge in: the mass of liquid, followedimmediately by a drop in pressure below the-minimum holding pressure.Without such a time delay, the pressure-responsive device wouldautomatically cut oli the supply of compressed gas to the pump systemimmediately after the surge when the drop in pressure below the minimumholding pressure occurs.

However, in the unique case when the compressed gas is introduced atexactly such a rate as to immediately create a back pressure higher thanthe minimum holding pres sure and to uniformly accelerate the mass ofliquid to maintain a dynamic back pressure without surges and subsequent pressure drops-below the minimum holding pressure, the controlsystem can operate in a threestage cycle asfollowszw I i l x In thefirststage, the liquid actuates the control-apparatus by (a) physicallydisplacing an actuating member bymeans of a bell (FIGS. 1 and 2), afloat, or another liquid displacing body; or by (b) contacting anelectrode and completing an electrical circuit (FIGS. 3 and 4).

In the second stage of the cycle, the control apparatus is held inoperative position by dynamic back pressure.

In the last stage, the control apparatus is released by reducing thedynamic back pressure below the holding ressure, i.e. below the pressurerequired to maintain the control apparatus in such position that thelatter permits introduction of compressed gas into the pump system.

To eliminate the effects of all unknown and uncontrollable factors, a'fourth stage is now introduced between the first and the'second stagesabove referred to, along with a fifth stag'e' between theabove-mentioned second and third stages.- The influence of such unknownand uncon-i trollable factors is eliminatedby' the aforementioned timedelay device which maintains the first stage (completion of electricalcircuit or actual displacement oi a float or the like) until thepressure, in accordance with the requirements of the second stage, isbuilt up sufiiciently to reach the desired holdingpressure with onlystatic pressures; The control system then operates in a five-stage cycleas follows: r

First stage is the same as above.

In the second stage, the time delay device maintains the elements in theposition they assumed in the first stage.

In the third stage, static back pressure further maintains the elementsof control apparatus in theposition's they atesurned-inthefirst twostages.--- I In the fourth stage, the time delay is released.

Finally, in the last stage, as in the third stage hereinbeforedescribed, the control system is released by reducing the back pressurebelow the holding pressure.

The sensing or starting device of the hydraulic control system of FIG. 2is shown installed in the pct 14 of pump 10 which is illustrated in FIG.1, it being understood, however, that it can be used in the controlchamber 26 of the modified pump 10:: shown in FIG. without anymodifications. Similarly, the electrical sensing or starting devicesillustrated in FIGS. 3 and 4 as forming part of the pump system It canbe used in the pump a; this will be readily understood as thedescription proceeds.

The sensing or starting device 20 is in the form of a bell which isfastened to the lower and externally threaded end of actuating elementor stem 23 of pilot valve 27 by means of nuts 29,. 30. Valve 27 formspart of the control system for introducing compressed gas into thereceiver. A back pressure line 31 communicates with the interior of pot14; its pilot branch 32 is connected with the pilot valve 27, and itstime delay branch 33 connects the line 31 with the upper end of timedelay 34 whose cylinder 35, is integral with the housing of valve 27.The time delay 34 further comprises a piston 36, poppet system 37,poppet 38, liquid delaying medium 39, and a seal 4t). The control systemfurther comprises a pilot gas pressure line 41, a pilot-actuating gasline 42, and a main valve 43. The latter comprises an actuating memberor stem 44, a diaphragm 45' (replaceable by a piston), and weight orweights 46.

It will be noted that only pct 14, bell 20 and the time delay 34 areshown in section, the pilot valve 27 and the main valve 43 beingcommercially available devices of known construction. Pilot valve 27 isa three-way spool valve with a mid-point neutral position in which allthree ports (indicated by letters C, P and E) are closed at the sametime. The stem 28 is shown approximately midway between its two extremepositions. The markings C, P and E shown .on the pilot valve 27 aredesignations well known and accepted in industry for this type ofthree-way valve and dasignate the cylinder side C, the pressure side P,and the exhaust side B, respectively, of the valve. When the valve stem28 is in down position, the C side is open to the E side, and the P sideis closed. As the stem 28 travels in upward direction, it shuts off sideC to side E before opening side C to side P in the up position.

The main valve 43 is of similar construction with the exception that itis usually larger and its stem 44 is actuated by a diaphragm 45 which,as before stated, may be replaced by a piston (not shown) to move thestem 44 in upward direction. The weight or weights 46 cause the stem 44to descend when no pressure is applied against the underside ofdiaphragm 45. The C, P and E designations have the same meaning as thoseapplied to pilot valve 27.

The friction in the valves is rather negligible and, therefore, need notbe taken into account in the following description of operation of thecontrol system shown in FIG. 2. The weight of element 46 plus the weightof the stem 44 are equal to the effective area of diaphragm 45 times theminimum holding pressure of pump 1%. Time delay 34 is actuated by thevalve stem 28 which latter is directly connected with the poppet stem37. Poppet stem 37 is free to slide in the piston 36 which in turn isloosely slidable in the cylinder 35. There is an annular clearance 47between the periphery of piston 36 and the inner wall of cylinder 35.The sliding movement of the piston-36 with respect to poppet stem 37 isvery short and is limited on one side by the valve stem 28 which definesa shoulder 48, and on the other side by the poppet 38. Piston 36 hasbypass apertures 49 which allow the liquid delaying medium 39 to passfrom the underside of piston 36 when the piston rests againstshoulder-48 onthevalve stem 28. If the piston rests against the poppet38, the latter closes apertures 49. and

thus prevents communication of medium 39 to the upper side of thepiston. When the valve stem 28-is in its down position, piston 36 restsagainst the face 50 of cylinder 35. As the pilot valve stem moves inupward direction, its shoulder 48 engages and entrains the piston 36,thus opening the lower terminals of apertures 49-to permit the passageof liquid delaying medium 39 from the upper side to the underside of thepiston. The liquid delaying medium 39 otters little resistance to thetravel of piston 36.

When the valve stem 28 reaches the upper end of its stroke and thereuponbegins to descend underits own weight, as well as under the weight ofpoppet stem 37, poppet 3S and bell 20, the slight resisting force ofliquid delaying medium 39 holds the piston 36 in its uppermost positionuntil the poppet 38, traveling with valve stem 23, engages the upperface of the piston and closes the upper terminals of apertures 49. Topermit further travel of the valve stem 28 in downward direction, liquiddelaying medium beneath the piston 36 must be displayed by flowing aboutthe periphery of latter through the annular clearance 47. This clearanceis small enough to offer relatively high resistance to the flow of saidmedium, thus slowing down the movement of valve stem 28 at such rate asto suificiently delay the opening'of the C side to the E side in pilotvalve 27.

While the pump 10 is filling, i.e. while the valve 12 shown in FIG. 1 isopen, the displaced gas flows from the pot 14 and through the gas pipe19 into the main valve 43 and to atmosphere through the exhaust side Ewhich is open to the cylinder side C.

Side P of the main valve 43 is then closed. The stem 28 of pilot valve27 is in its down position with its side C open to side E, and the sideP closed. As the liquid level rises in the pot 14, it entraps a certainquantity of air in the bell 20. For all practical purposes, and byneglecting friction, the force necessary to move the stem 28 of pilotvalve 27 equals the combined weight of the valve stem and of bell 20 sothat the bell must displace an amount of liquid whose weight equals thecombined weight of the bell'and valve stem 28. This is achieved when theliquid level reaches line C-C which is below the lower terminal of gaspipe 19. Thus, the pilot valve 27 always operates beforethe liquid couldreach the terminal 51. Should there be a failure in gas supply and theliquid level would continue to rise, it will, upon reaching the terminal51, rise in the pipe 19 but not in the pot 14 since the only path forescape of gases from the pot 14 is then closed at the E side of pilotvalve 27. In this manner, floating solids are prevented from reachingthe top of hell 26. Such solids carried by the liquid, for example, rawsewage, would add to the overall weight of the bell 24 plus valve stem28 and would thus upset the operation oi the control apparatus.

When the pilot valve stem 28 is moved into up position, i.e. when undernormal operating conditions the liquid level in the pot 14 reaches lineC--C, side C of pilot valve 27 is closed to side E, and the side C isopen to side P. The compressed gas in line 52 is permitted to passthrough pilot gas pressure line 41, from the P side to the C side ofpilot valve 27, and through pilot actuating gas line 42 to actuate themain valve 43 by acting against the underside of diaphragm 45 to liftthe valve stem '44 against the action of weight 46. Side P in the mainvalve 43 is then open to side C to permit compressed gas in line 52 toenter conduit 19 and therethrough into the pot 14. The side C of mainvalve 4 is then closed to side E.

While the gas is building up a back pressure equal to or greater thanthe minimum holding pressure in pot 14, pilot valve stem 23 is held inup position by time delay 34 and descends only slowly to down.positionin which the side P of valve 27 is, shut on and side C opensv to side E,allowingback pressure instead of press sure in line 52 to hold the stem44 of main valve 43 in up position.

In its simplified form, and in accordance with the disclosure ofaforementioned Patent No. 2,656,794, the control apparatus of FIG. 2 canalso operate without the time delay 34. The stem 28 of pilot valve 27then descends together with the liquid level. The main drawback of suchsimplified construction is in that the pressure responsive device mayinterrupt the gas supply at a time when the receiver is only partlyevacuated. In either case, the back pressure line 31 with its branchline 32 equalizes the pressure at both sides of the pilot valve stem 28,so that the forces resulting from the pressure times the cross-sectionalarea of the stem which act in opposing directions cancel each other anddo not affect the operation of pilot valve 27.

When the back pressure is reduced to a point below the minimum holdingpressure, stem 44 of the main valve descends under the influence of itsown weight plus that of weight 46, and closes side C to side P whileopening side C to side E of main valve 43. This completes the cycle andthe air is again free to escape up the line 19 and from side C to side Eof the main valve.

ln FIG. 3, there is shown an electrically operated con trol apparatusforthe pump 10 of FIG. 1. This system, too, is adapted to temporarilymaintain the supply of compressed gas (e.g., air) to the control chamber26 of the pump 10a shown in FIG. 5, after the liquid therein has reacheda critical level.

The bell 20 shown in FIGS. 1 and 2 is replaced by a control electrode 53which is insulated from the metallic wall of the pot 14 by a suitableinsulating element 54. Electrode 53 is connected through the winding ofa relay 55 to a source of current here shown schematically as thenegative terminal of a battery 56 whose positive terminal is grounded. Abus bar 57 terminates at the front contact of relay 55 whose armature 55is likewise connected to the high-voltage terminal of battery 56.

Connected between bus bar 57 and ground are the windings of' aslow-operating relay '3 and of a start relay 59. Armature 65) of relay59, whose from contact is tied to bus bar 57, is connected to negativebattery via an armature 61 and back contact of relay 58 and, in paralleltherewith, through a normally open contact 63 of a pressure switch 62here shown as comprising a diaphragm 64 within a cylinder 65communicating with the interior of pot 14 by way of a conduit 66; Relay59 has three further armatures 67, 63, 69 connected to respectiveterminals of a source 70 of alternating current, here indicatedschematically as a three-phase generator; the front contacts associatedwith these armatures lead to respective phase windings of an A.-C. motor71.. A compressor 72 driven by motor 71 via a transmission,schematically indicated at 73, supplies air under pressure to a duct 74.

Duct 74 leads into gas pipe 19 by way of a springloaded check valve 77.Ahead of valve 77, a pilot duct 78 branches off from duct 74 and leadsto a normallyopen two-way diaphragm valve 79 controlling an outlet port19' of pipe 19.

When the liquid in pot 14 has risen sufficiently to contact theelectrode 53, it closes a high-resistance path between this electrodeand the grounded wall of the pot, thereby energizing the highlysensitive relay 55. This relay attracts its armature 55 and connects busbar 57 to the negative terminal of battery 56. Start relay 59 is nowenergized, but relay 58 connected in parallel with relay 59 is slow torespond so that a holding circuit forrelay 59 is closed via its armatureand armature 61 to negative battery. Relay 59, at armature 67, 68, 69,also connects power to motor 71 which now drives the cornpressor 72,whereby air under pressure is admitted through check valve 77 into gassupply pipe 19 and through pilot duct 78 to valve 79, the latteroperation lid shutting off pipe 19 from the atmosphere by closing theduct 19'. As the liquid level in pot 14 begins to drop, relay 55releases but relay 59 remains operative over its previously tracedholding circuit.

Before the slow-operating relay 55 has yet attracted its armature 61,the back pressure in pot 14 has built up sufliciently to cause theoperation of pressure switch 62 which closes the contact 63, therebymaintaining the holding circuit of relay 59 even after relay 58 hasoperated. "this holding circuit is broken only when the pressure in pot1% has dropped below its critical value, the resulting release of relay59 deenergizing motor 71 to restore the system to its quiescentcondition.

The circuit of FIG. 4 is similar to that of FIG. 3, except that relay 59has been replaced by a relay 80 having a single armature 81. Motor 71 ofFIG. 3 has been omitted, fiuid under pressure having been assumed toenter the duct 52 from a suitable source (not shown) as in FIG. 2. Asolenoid 82 is connected between bus bar 57 and ground, this solenoidcontrolling the stern of a pilot valve 83; the latter valve is insertedbetween a pilot duct 84 which branches ofi from main gas line 52, and aconduit 85 leading toward the main valve 43 to control its operation inthe manner desiribed for pilot valve 27. and main valve 43 of FIG. 2.

In operation, the rise of the liquid in pct 14- toward electrode 53again results in the operation of relay 55 which energizes the relay 8%)and, after an interval, the slow-operating relay 58 as previouslydescribed. Relay 80, in attracting its armature 81, closes itsaforedescribed holding circuit and maintains bus bar 57 connected tonegative battery independently of relay. Before relay 58 has operated toopen the holding circuit of relay 80, armature 61 has been shunted bycontact 63 as a result of the operation of pressure switch 62. Solenoid82, operating in parallel with relay 8t}, admits gas from duct 52 intopipe 19 and maintains its operative position until the back pressure inpot 14 has dropped sufliciently to deactivate the switch 62 and torestore the circuit to normal. In FIG. 5, there is illustrated a liquidevacuation pump 18a which is quite similar to that shown in FIG. 1, withthe exception that the inflowing liquid is stored in a control chamber26 and in a receiver pipe 15 which thus replace the pot 14.

The operation of pump Ida is identical with thatof the previouslydescribed pump 10. Thus, liquid enters through inlet pipe 11a and valve12a to fill the lines 11a, 15 and 17a, as well as chamber 26 up to thelevel C'-C when the control element 26a becomes operative to close line19a to atmosphere and introduce compressed gas therethrough. Controlelement Zila schema tically represents either the bell 26 (FIGS; 1 and'2) or the electrode 53 shown in FIGS. 3 and 4. The liquid underpressure in inlet trap 13a then closes valve 12a while the compressedgas expels the liquid frorn chamber 26 and line 15 through dischargetrap 16a and lines 17a, 18a into the gravity main 22a. Spent gas is freeto escape through discharge chamber 21a. When the liquid level isreduced to line DD', after which the gas expansion takes place, nearlyatmospheric pressure prevails in the chamber 26 and line 15 which causesthe element Zila to open line 19a to atmosphere and to interrupt thesupply of compressed gas therethrough; Lines A'--A' and B indicate theinitial levels of liquid in the respective traps 16a and 13a.

7 It has been discovered that the shape and inclination of certainhereinabove described parts greatly influence the operation of the pump10a. Thus, the diameter and slope of receiver line 15; the curvature ofcontrol chamber 26 at points 23, 24 and 25; as well as the inclination,if any, of gas expansion pipe 17a from the .vertical affect theoperation of the pump. The inclination of receiver line 15 and the shapeof control chamber 26 in areas indicated by numerals 23 to 25 areimportant for the maximum rate of flow of liquid which can passthroughthe inlet pipe 11a. The receiver 15 must be of such diameter andslope that the maximum flow of incoming liquid only partially fills itscross-sectional area, thus allowing the airto escape in a directionopposite to the liquid how when the line is filling. In other words,when the check valve 12a is open, air must be free. to flow fromreceiver line 15 into the control chamber 26 and thence into and throughthe line 19a which is open to atmosphere. For the above reason, thediameter of receiver line 15 preferably is at least one pipe size largerthan the diameter of inlet line 11a.

The shape of control chamber 26 in the areas indicated by numerals 23,24 and 25 is so chosen as to allow liquid at this rate of flow to passthrough the chamber 26 without bunching up, as the accumulated liquidwould hinder the escape of gas from receiver line 15 into the controlchamber 26. At 24, the piping expands and is broader than the inletpiping 11a, enabling the incoming liquid to spread out as it passesthereover. At 23, the chamber '26 curves upwardly to allow unimpededpassage of gas. The velocity of incoming liquid increases by gravity asit flows over area 25, which reduces the contained vertical head of theliquid.

As is described and claimed in the hereinbefore mentioned United StatesPatent No. 2,656,794, an advantage of the system shown in FIG. is inthat it requires no separate ejector pots since the liquid assemblies inthe receiver line 15 which forms part of the piping for conveying theliquid from a lower to a higher level. This system requires no checkvalve at the discharge end of the receiver. Substantial quantities ofliquid, accumulated in the line 15 between traps 13a and 16a, may belifted to a higher level within a very short period of time, as abovementioned in connection with the pumping apparatus shown in FIG. 1.

The invention is, of course, not limited to the exact details ofconstruction illustrated and hereinabove described, but may be embodiedin a number of further modifications within the spirit and scope of theappended claims.

I claim:

1. A pneumatic pumping apparatus comprising, in combination, a receiver;conduit means connected to said receiver for introducing a liquid intosaid receiver; one-way valve means in said conduit means; piping incommunication with said receiver at a lower portion thereof andextending upwardly therefrom; a source of compressed gas; a line incommunication with said receiver and adapted to be alternately connectedwith atmosphere and with said source; control means operativelyconnected to said line and having a first position in which said line isopen to atmosphere and a second position in which said line introducescompressed gas into the receiver to close said one-way valve means andto expel the liquid through said piping; starting means actuatable bythe liquid when the latter fills said receiver to a predetermined levelcausing movements of the control means into said second position; timedelay means operatively connected with said starting means formaintaining the control means in said second position for a fixed periodof time; and means for moving said control means into said firstposition in response to a predetermined minimum pressure in saidreceiver after said time delay means becomes deactivated.

2. In a sewage ejector, in combination: a sewage receiver having anupper portion and a lower portion; conduit means connected to the lowerportion of said receiver for introducing sewage therein; one-way valvemeans in said conduit means; a pipe connected to the lower portion ofsaid receiver and extending upwardly therefrom; a source of compressedgas; a line communicating with the upper portion of the receiver andconnected with said source; control means in said line having a firstposition in which the line connects said receiver with atmosphere andasecond position in which the receiver is connected with said source;starting means in the upper portion of said receiver and actuatable bythe sewage when the latter fills the receiver to a predetermined levelfor moving said control means into the second position whereby gas isintroduced into the receiver and sewage closes said oneway valve meansand is expelled into and through said pipe; time delay means operativelyconnected with said starting means and actuatable thereby when thecontrol means is moved into said second position, said time delay meansbeing further operatively connected with the control means formaintaining same in said second position for a fixed period of time; andmeans for moving the control means into said first position after thetime delay means becomes deactivated, said last mentioned means beingresponsive to a predetermined minimum pressure in said receiver. 7

3. In a sewage ejector, in combination,. an ejector pot having an upperend and a bottom; an inlet pipe connected with said pot at the bottomthereof for introducing sewage by gravity flow therein; a one-way valvein said inlet pipe; a sewage evacuating pipe connected with said pot atits bottom and extending upwardly therefrom in substantially verticaldirection; a source of compressed gas; a line communicating with saidpot close to its upper end and connected with said source of compressedgas; control means including at least one valve in said line, said lastnamed valve having a first position in which the line connects said potwith atmosphere and a second position in which the line introducescompressed gas from said source into the pot; starting means disposed insaid pot in the proximity of the upper end thereof and actuatable by thesewagewhen the latter fills the pot to a predetermined level, saidstarting means being operatively connected with the control means insuch a way as to move the last mentioned valve into said second positionwhereby to introduce compressed gas into the 'pot to expel the sewagethrough said evacuating pipe; a time delay means actuatable by thestarting means and connected with the control means in such a way'as tomaintain the last mentioned valve in said second position for a fixedperiod of time; and a pressure-responsive device connected with the potand with the control means in such a way as to move the last mentionedvalve into said first position after the time delay means becomesdeactivated and the pressure in said pot drops to a predeterminedminimum level.

4. A pneumatic pumping apparatus comprising, in combination, a receiver;conduit means for introducing a liquid into the receiver; an inlet trapin said conduit means adjacent to and below the level of said receiver;one-way valve means in the conduit means on the upstream side of saidtrap; piping in communication with said receiver at a lower portionthereof and extending upwardly therefrom; a source or" compressed gas; aline in communication with the receiver and adapted to be a ternatelyconnected with atmosphere and with said source; control meansoperatively connected to saidline and having a first position in whichthe line is open to atmosphere and a second position in which the lineintroduces compressed gas into the receiver to close said oneway valvemeans and to expel the liquid through said piping; starting meansactuatable by the liquid when the latter fills the receiver to apredetermined level for moving the control means into said secondposition; time delay means actuatable by said starting means formaintaining the control means in said second position for a fixed periodof time; and means for moving the control means into said first positionin response to a predetermined minimum pressure in the receiver afterthe time delay means becomes deactivated. Y 5. In a pumping devicehaving a receiver, inlet piping forintroducing a liquid into thereceiver, one-way valve means in said piping, and discharge pipingconnected to said receiver at a lower portion thereof and extending '13upwardly from said receiver, in combination, a source of compressed gas;conduit means connecting the source with said receiver; valve means insaid conduit means including a vent port and actuating means, saidactuating means having a position of rest in which the receiver isclosed to said source and open to atmosphere through said vent port, anda second position in which the conduit means permits flow of gas intothe receiver and said vent port is closed; piping connected with saidsource and with the receiver and so disposed with. respect to saidactuating means that gas under pressure therein moves the actuatingmeans into said second position; second valve means in said piping foralternately closing the piping to said source and to said receiver,respectively; starting means in said receiveroperatively connected withthe second valve-means for normally maintaining the latter in a firstposition in which the piping is closed to said source and adapted to' beactuated by a liquid in said receiver when the liquid-reaches apredetermined level in the latter whereby to move the second valve meansinto a second position -in which the latter closes the piping to saidre- .ceiver; and time delay means for maintaining the second valvemeans'in said second position for a fixed period "of time."

6. ha pumping device having a receiver, an inlet pipe gas; afirst valvehaving a vent port, a diaphragm, and an actuating-member connected withsaid diaphragm, said actuating member having a position of rest and asecond position; a first line for connecting the valve with saidreceiver; a second line for connecting the valve with said source, saidsecond line being open to the first line when the actuating member is inits second position and the first line being open to said vent port whenthe actuating member is in position of rest; a second valve having afirst port, a second port, a third port, and an actuating elementextending into the receiver and having a first position in which thefirst port communicates with the second port and a second position inwhich the first port communicates with the third port; a first pipe forconnecting the first port with said diaphragm; a second pipe forconnecting the second port with said source; a third pipe for connectingthe third port with said receiver; a float in the receiver attached toand normally maintaining the actuating element in its second positionand adapted to be lifted by a liquid at a predetermined level for movingthe actuating element into its first position; and a time delayoperatively connected with the actuating element for retarding themovement thereof from its first into its second position, said pumpingdevice operating in such a way that, when the actuating element is movedby the float into its first position, the gas from said source moves thediaphragm and the actuating member into the second position, gas isintroduced into the receiver and expels the liquid through the outletpipe, the time delay retarding the movement of the actuating elementinto the second position whereupon gas in the receiver maintains theactuating member in its second position until the liquid is evacuatedfrom the receiver and the gas is free to escape through the outlet pipeto permit return of the actuating member into its position of rest.

7. The combination according to claim 6, wherein said second pipecommunicates with said second line.

8. The combination according to claim 6, wherein said receiver is a pothaving an upper end and a lower end, said inlet pipe and said outletpipe being connected to the lower end of said pot, and said first lineand said third pipe being. connected to the upper end of said pot.

1 1 '9. The combination according to claim 8, wherein said actuatingelement extends vertically downwardly into said pot and said float is abell attached to the lower end of said actuating element.

10. The combination according to claim 6, wherein said 'inlet pipedefines an inlet trap adjacent to and below the level of said receiver,and said one-way valve means is on the upstream side of said trap.

11. The combination according to claim 6, wherein said outlet pipeextends substantially vertically from said receiver.

horizontal and having an upper end and a lower end; said inlet pipe,said first line and said third pipe being connected to said tubularelement adjacent to the upper end thereof; said outlet pipe beingconnected to the lower end of said tubular element; and said actuatingelement is located in the proximity of'the upper end of said tubularelement.

15. The combination according to claim 6, wherein said receivercomprises an elongated tubular element inclined from horizontal andhaving an upper end and a lower end, and a chamber having an upper endand a lower end with the latter in communication with the upper end ofsaid tubular element, said inlet and said outlet pipe being connected tothe upper and lower end ofsaid tubular element, respectively, said firstline and said third pipe communicating with the upper end of saidchamber, and said actuating element extending vertically into the upperend of said chamber.

16. The combination according to claim 6, wherein said actuating elementis mounted for vertically reciprocating movements and said time delaycomprises a stem rigidly fixed to said actuating element, a casingsurrounding said stern and defining an enclosure, a liquid substancesubstantially filling said enclosure, and perforated means carried bysaid stem and so installed in said enclosure that the liquid substanceretards movements of said stem in one direction and offers relativelylittle resistance to the movements of said stern in the other direction.

17. The combination according to claim 6, wherein said actuating elementis mounted for vertically reciprocating movements and said second valvecomprises a housing having an upper end through which said actuatingelement extends, said time delay comprising a casing defining anenclosure adjacent to and above said housing, a lower wall in saidenclosure, a stem connected with said actuating element and reciprocablein said enclosure, said stem having an enlarged head at its upper endand defining a radial shoulder spaced from said head, a piston member'disposedabout said stem and slidable between said head and saidshoulder, said piston member having a peripheral Zone slightly spacedfrom said casing and at least one bore so disposed as to have one endclosed by said lower wall when the piston member is. in lowermostposition in said enclosure and another end closed by said head-when thepiston member is in its uppermost position with respect to said stem,and a liquid substance substantially filling said enclosure.

18. The combination according to claim 17, further comprising a conduitin communication with said receiver and with the upper end of saidenclosure.

19. The combination according to claim 18, wherein said last mentionedconduit is connected to said third pipe.

20. The combination according to claim 6, wherein said outlet pipe isvented above said receiver.

21. A pneumatic pumping apparatus comprising, in combination, areceiver; conduit means for connecting said receiver with a source ofliquid; one-way valve means in said conduit means; discharge piping incommunication with said receiver at a lower portion thereof andextending upwardly therefrom; a source of compressed gas; a line incommunication with said receiver; control means in said line foralternately connecting same with said source and with atmosphere,respectively; electrical starting means operatively connected to saidcontrol means comprising a source of electric current and an electrodeextending into said receiver, said starting means operating in suchmanner as to cause the control means to connect said line with thesource of compressed gas when the electrode is contacted by a liquid insaid receiver; electric time delay means connected with said electrodefor maintaining for a fixed period of time said control means in aposition in which the line is connected to said source; and pressureresponsive means operatively connected with the receiver and with thecontrol means and operating in such a way as to cause said control meansto connect the line with atmosphere in response to a predeterminedminiw'mum pressure in said receiver after said electric time delay meansbecomes deactivated.

22. A pneumatic pumping apparatus for use as a liquid ejector whichcomprises, in combination, a receiver; inlet piping for introducing aliquid into the receiver; one-way valve means in said piping; dischargepiping in communication with said receiver at a lower portion thereofand extending upwardly therefrom; a source of compressed gas; a line incommunication with the receiver; control means in said line foralternately connecting same with said source and with atmosphere,respectively; starting means operatively connected with said controlmeans and comprising a source of electric current and electrode meansextending into said receiver in such a way as to be contacted by theliquid therein when the liquid rises to a predetermined level to closethe circuit of said electrode means and to cause said control means topermit flow of compressed gas into the receiver; electric time delaymeans comprising relay means in the circuit of said electrode means anda holding circuit for maintaining closed the circuit of said electrodemeans for a fixed period of time after the latter is contacted by theliquid in said receiver 'whereby the flow of gas into the receiver iscontinued; and pressure responsive means in the circuit of saidelectrode means and operatively connected with said receiver *forbreaking the circuit of said electrode means in response to apredetermined minimum pressure in said receiver whereby said controlmeans interrupts the fiow of compressed gas into the receiver andconnects said line with atmosphere after said electric time delay meansbecomes deactivated.

23. A' pneumatic pumping apparatus for use as a liquid ejector whichcomprises, in combinatlon, a grounded receiver; inlet piping forintroducing a liquid into the receiver; one-way valve means in saidpiping; discharge piping in communication with the receiver at a lowerportion thereof and extending upwardly therefrom; a line incommunication with the receiver; a compressor connected with said line;an electric motor connected to said compressor; an electrical sourceadapted to be connected to said electric motor; a check valve in saidline; a first conduit communicating with said line intermediate saidcheck valve and said receiver; a second conduit communicating with saidline intermediate said compressor and said check valve; pressureresponsive valve means between said first and said second conduit forclosing the first conduit to atmosphere when compressed gas isintroduced into said line and into said second conduit 'by saidcompressor, and for opening said first conduit to atmosphere whensubstantially atmospheric pressure prevails in said second conduit; anelectric circuit for said compressor and said electric motor furthercomprising a starting electrode insulated from and extending into saidreceiver to be contacted by a liquid when the latter rises inthe'receiver to a predetermined level, a source of electric current,electric time delay means including relaymeans, a holding circuit formaintaining said electric motor electrically connected with said cornpressor over said time delay means for a fixed period of time, andpressure responsive switch means operatively connected wi h saidreceiver, said apparatus operating in such a way that the liquid, uponcontacting the electrode, closes a high resistance path between saidelectrode and said receiver to close said circuit and to actuate saidtime delay means and to connect said electric motor with saidcompressor, the compressor supplying gas under pressure through saidline into the receiver and causing said pressure responsive valve meansto close said first conduit to atmosphere, said time delay meansmaintaining the connection between the electric motor and the compressorfor a fixed period of time whereupon said switch means breaks thecircuit to stop said compressor in response to a predetermined minimumpressure in the receiver.

24. A pneumatic pumping apparatus for use as a liquid ejector whichcomprises, in combination, a grounded receiver; inlet piping forintroducing a liquid into the receiver; one-way valve means in saidpiping; discharge piping in communication with the receiver at a lowerportion thereof and extending upwardly therefrom; a line incommunication with said receiver;a source of compressed gas connected tosaid line; a pilot valve connected to said line comprising an actuatingmember having a position of rest in which said pilot valve opens theline to atmosphere and closes the line to said source, and a secondposition in which the line communicates with said source and is closedto atmosphere; starting means for moving the actuating member into saidsecond position, said starting means comprising an electrode insulatedfrom and extending into the receiver to be'contacted by a liquid thereinwhen the liquid rises to a predetermined level and closes a highresistance path between the electrode and the receiver; time delay meansincluding relay means in the circuit of said electrode and energizableby said electrode when the latter is contacted by liquid in thereceiver, said time delay means being connected with said starting meansfor maintaining the actuating member in said second position for a fixedperiod oftime; and pressure responsive switch means in the circuit ofsaid starting means and operatively connected with said receiver forbreaking the circuit of said starting means in response to apredetermined minimum pressure in the receiver whereupon the actuatingmember returns into said position of rest.

25. A liquid ejector comprising, in combination, a receiver; inletpiping for introducing a liquid into the receiver and comprising meansfor preventing the return flow of liquid therethrough; discharge pipingfor evacuating the liquid connected to said receiver at a lower portionthereof and extending upwardly therefrom; a source of compressed gas; aline for connecting the source with said receiver; starting meansoperatively con nected with the receiver and actuatable by the liquidtherein when the latter rises to a given level, said starting meansbeing further connected with said source for causing the flow of gasinto the receiver in response to rise of liquid in the receiver to saidlevel; time delay means operatively connected with said starting meansand with said source for maintaining the flow of gas into the receiverfor a fixed period of time after the liquid therein reaches said level;and means operatively connected with the receiver and with said sourcefor interrupting the flow of gas into said receiver in response to apredetermined minimum pressure therein after said time delay meansbecomes deactivated.

References titted in the file of this patent UNITED STATES PATENTS1,025,727 Wells May 7, 1912 1,157,491 Anderson Oct. 19, 1915 1,739,511Kramer Dec. 17, 1929 (fisher references on following page) 17 UNITEDSTATES PATENTS Hatfield Nov. 26, 1940 Miller Oct. 7, 1941 De Witt Aug.10, 1943 Elliot Dec. 17, 1946 5 Williamson Oct. 27, 1953 18 StaffordFeb. 23, 1954 Cibat-tari Dec. 6, 1955 Yeomans Jan. 17, 1956 Weis Dec.24, 1957 Griffith June 30, 1959 Franey July 28, 1959

1. A PNEUMATIC PUMPING APPARATUS COMPRISING, IN COMBINATION, A RECEIVER;CONDUIT MEANS CONNECTED TO SAID RECEIVER FOR INTRODUCING A LIQUID INTOSAID RECEIVER; ONE-WAY VALVE MEANS IN SAID CONDUIT MEANS; PIPING INCOMMUNICATION WITH SAID RECEIVER AT A LOWER PORTION THEREOF ANDEXTENDING UPWARDLY THEREFROM; A SOURCE OF COMPRESSED GAS; A LINE INCOMMUNICATION WITH SAID RECEIVER AND ADAPTED TO BE ALTERNATELY CONNECTEDWITH ATMOSPHERE AND WITH SAID SOURCE; CONTROL MEANS OPERATIVELYCONNECTED TO SAID LINE AND HAVING A FIRST POSITION IN WHICH SAID LINE ISOPEN TO ATMOSPHERE AND A SECOND POSITION IN WHICH SAID LINE INTRODUCESCOMPRESSED GAS INTO THE RECEIVER TO CLOSE SAID ONE-WAY VALVE MEANS ANDTO EXPEL THE LIQUID THROUGH SAID PIPING; STARTING MEANS ACTUATABLE BYTHE LIQUID WHEN THE LATTER FILLS SAID RECEIVER TO A PREDETERMINED LEVELCAUSING MOVEMENTS OF THE CONTROL MEANS INTO SAID SECOND POSITION; TIMEDELAY MEANS OPERATIVELY CONNECTED WITH SAID STARTING MEANS FORMAINTAINING THE CONTROL MEANS IN SAID SECOND POSITION FOR A FIXED PERIODOF TIME; AND MEANS FOR MOVING SAID CONTROL MEANS INTO SAID FIRSTPOSITION IN RESPONSE TO A PREDETERMINED MINIMUM PRESSURE IN SAIDRECEIVER AFTER SAID TIME DELAY MEANS BECOMES DEACTIVATED.